The eighth-seeded 22-year-old Dimitrov, the youngest member of the ATP's Top 20, held off Russian veteran Dmitry Tursunov 6-2, 1-6, 6-4, while Dutch crowd favorite and wild card Igor Sijsling easily took out the Russian Youzhny, the 2007 champion and 2010 runner-up, 6-2, 6-2, on the indoor hardcourts at Ahoy Rotterdam.

Up next for the in-form Cilic on Wednesday will be fifth-seeded 2011 Rotterdam finalist Jo-Wilfried Tsonga.

This week's top seeds are the reigning Rotterdam champion and former U.S. Open winner del Potro and reigning Wimbledon titlist and 2009 Rotterdam champ Andy Murray. Del Potro will open his week against last week's Montpellier champ Gael Monfils, while Murray will encounter France's Edouard Roger-Vasselin in the round of 32 on Wednesday.